Author Archives: gutsandgrowth

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About gutsandgrowth

I am a pediatric gastroenterologist at GI Care for Kids (previously called CCDHC) in Atlanta, Georgia. The goal of my blog is to share some of my reading in my field more broadly. In addition, I wanted to provide my voice to a wide range of topics that often have inaccurate or incomplete information. Before starting this blog in 2011, I would tear out articles from journals and/or keep notes in a palm pilot. This blog helps provide an updated source of information that is easy to access and search, along with links to useful multimedia sources. I was born and raised in Chattanooga. After graduating from the University of Virginia, I attended Baylor College of Medicine. I completed residency and fellowship training at the University of Cincinnati at the Children’s Hospital Medical Center. I received funding from the National Institutes of Health for molecular biology research of the gastrointestinal tract. During my fellowship, I had the opportunity to work with some of the most amazing pediatric gastroenterologists and mentors. Some of these individuals included Mitchell Cohen, William Balistreri, James Heubi, Jorge Bezerra, Colin Rudolph, John Bucuvalas, and Michael Farrell. I am grateful for their teaching and their friendship. During my training with their help, I received a nationwide award for the best research by a GI fellow. I have authored numerous publications/presentations including original research, case reports, review articles, and textbook chapters on various pediatric gastrointestinal problems. In addition, I have been recognized by Atlanta Magazine as a "Top Doctor" in my field multiple times. Currently, I am the vice chair of the section of nutrition for the Georgia Chapter of the American Academy of Pediatrics. In addition, I am an adjunct Associate Clinical Professor of Pediatrics at Emory University School of Medicine. Other society memberships have included the North American Society for Pediatric Gastroenterology Hepatology and Nutrition (NASPGHAN), American Academy of Pediatrics, the Food Allergy Network, the American Gastroenterology Association, the American Association for the Study of Liver Diseases, and the Crohn’s and Colitis Foundation. As part of a national pediatric GI organization called NASPGHAN (and its affiliated website GIKids), I have helped develop educational materials on a wide-range of gastrointestinal and liver diseases which are used across the country. Also, I have been an invited speaker for national campaigns to improve the evaluation and treatment of gastroesophageal reflux disease, celiac disease, eosinophilic esophagitis, hepatitis C, and inflammatory bowel disease (IBD). Some information on these topics has been posted at my work website, www.gicareforkids.com, which has links to multiple other useful resources. I am fortunate to work at GI Care For Kids. Our group has 17 terrific physicians with a wide range of subspecialization, including liver diseases, feeding disorders, eosinophilic diseases, inflammatory bowel disease, cystic fibrosis, DiGeorge/22q, celiac disease, and motility disorders. Many of our physicians are recognized nationally for their achievements. Our group of physicians have worked closely together for many years. None of the physicians in our group have ever left to join other groups. I have also worked with the same nurse (Bernadette) since I moved to Atlanta in 1997. For many families, more practical matters about our office include the following: – 14 office/satellite locations – physicians who speak Spanish – cutting edge research – on-site nutritionists – on-site psychology support for abdominal pain and feeding disorders – participation in ImproveCareNow to better the outcomes for children with inflammatory bowel disease – office endoscopy suite (lower costs and easier scheduling) – office infusion center (lower costs and easier for families) – easy access to nursing advice (each physician has at least one nurse) I am married and have two sons (both adults). I like to read, walk/hike, bike, swim, and play tennis with my free time. I do not have any financial relationships with pharmaceutical companies or other financial relationships to disclose. I have helped enroll patients in industry-sponsored research studies.

A new GALD phenotype

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A previous post discusses gestational alloimmune liver disease (GALD) (The more you know the more you see) and provides a number of references.  Additional insight into GALD comes from a recent case report (Pediatrics 2012; 129: e1076-79).

In this report, ascites is recognized in utero at 29 weeks.  This ascites was determined to be due to compression of the vena cava by hypertrophy of the hepatic caudate lobe.  When the patient was delivered at 34 weeks gestation, additional testing revealed normal coagulation parameters, peak ferritin level of 750 ng/ml at day 19, and a nodular liver on ultrasonography.  The patient underwent a liver biopsy via minilaparotomy which confirmed cirrhosis but did not show evidence of iron overload.  Tests for a multitude of other liver diseases were negative.  Liver biopsy stains demonstrated C5b-9 complex in >95% of hepatocytes after treatment with monoclonal antibody.  The detection of a high level of C5b-9 neoantigen is highly specific for  GALD.  Clinically, the patient had spontaneous recovery.

Take home points:

1. While iron overload is a hallmark of GALD, it is likely a consequence and not a cause of this severe liver disease.

2. Identifying atypical GALD cases allows the institution of immunotherapy during future pregnancies which reduces the recurrence risk.

3. The phenotypic spectrum of GALD includes the following:

  • Neonatal liver failure with iron overload
  • Fetal liver failure and/or death with or without iron overload
  • Liver cirrhosis and mild neonatal liver disease without iron overload.  These patients likely require special stains (call Peter Whittington for these patients)

Quantifying Risk of PML with Natalizumab

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Given the limited number of treatment options for inflammatory bowel disease, when Natalizumab became available, there was a great deal of enthusiasm.  This quickly diminished as reports of progressive multifocal leukoencephalopathy (PML) emerged.  So far, I have not prescribed this agent.

Due to its efficacy for multiple sclerosis and IBD, there has been continued interest in understanding the risk for PML (NEJM 2012; 366: 1870-80, editorial pg 1938-39).

Key findings:

  • 212 cases of PML among 99,571 patients treated with natalizumab (2.1 cases per 1000)
  • Three main risk factors: positive JC-virus antibody, previous use of immunosuppressants, and receiving natalizumab more than 2 years

Patients who were negative for anti-JC virus antibodies had an incidence of 0.09 cases or less per 1000 patients.  Among patients who test positive for anti-JC virus antibodies, the risk remained <1 per 1000 patients if no use of immunosuppressants and 2 per 1000 if prior use of immunosuppressants during the first two years of therapy.  The risks were five-fold higher after 2 years in both groups.

While the risks are becoming more clear, the benefits of natalizumab are fairly well-established for multiple sclerosis.  Natalizumab decreased the annualized rate of relapse among patients with relapsing–remitting multiple sclerosis by 68%.

Additional references:

  • -NEJM 2009; 361: 1067, 1075, 1081.  Asymptomatic detection of JC virus common in urine noted in patients Rx’d with natalizumab (19% baseline to 63% on Rx); actual leukoencephalopathy ~1/1000 patients.
  • -Gastroenterol 2007; 132: 1672.  ENCORE trial.
  • -JPGN 2007; 44: 185. n=31 children/adolescents.  55% response, 29% remission; dosed at 3mg/kg.
  • -IBD 2007; 13: 2.  n=79.  Trial of combination natalizumab & infliximab.
  • -NEJM 2006; 354: 899, 911, 924.  Natalizumab slows progression of MS.  Risk of PML due to JC virus 1:1000 in 18 months of Rx.
  • -NEJM 2005; 353: 1912/1965.  Natalizumab not significantly effective for Crohn’s in this study
  • -NEJM 2005; 353: 362, 369, 375, 414.  3 cases of PML associated with Natalizumab
  • -JPGN 2004; 39: S49 [abstract 0107].  Natalizumab in 38 adolescents was effective (Hyams et al).
  • -Gastroenterol 2004; 126: 1574-81. review.  Natalizumab benefitted subjects with elevated CRP. (dosing 300mg every 4 weeks.)
  • -NEJM 2003; 24-32 & 68.  Natalizumab improved response rates in pts c Crohn’s dz (similar to infliximab).  Drug blocks alpha4 integrins which are required for lymphocytes to enter the intestine.
  • -Gastroenterol 2001; 121: 268-74. Infusion of 3mg/kg decreases CDAI in Crohn’s dz.

Live longer -drink more coffee

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In a previous post, I was impressed with some of the benefits of coffee (Drink Up!).  More good news for coffee drinkers: drinking coffee is associated with decreased mortality (NEJM 2012; 366: 1891-1904).  Full disclosure –I don’t even drink coffee & I am not being paid by industry!

This study examined a huge population, 5,148,760 person-years (1995-2008) among 229,119 men and 173,141 women in the NIH-AARP Diet and Health Study with participants aged 50-71 at baseline.  With age-adjusted models, if adjusted for smoking, an inverse association between coffee consumption and mortality was noted.  With 6 cups per day, the hazard ratio (HR) was 0.90 for men and 0.85 for women.  For 2-3 cups, the HRs were 0.94 and 0.95 respectively.

Declines in mortality were noted for heart disease, respiratory disease, stroke, injuries/accidents, diabetes and infections, but not for deaths from cancer.  However, while coffee is associated with improved mortality data, a causal role for coffee consumption in reducing mortality cannot be established with this study.

Related link:

http://www.cnn.com/2012/05/16/health/coffee-drinking-longer-life/index.html?hpt=hp_t2

Something new for blue (BRBNS)

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A case report describes the use of low-dose sirolimus (rapamycin) for treating blue rubber bleb nevus syndrome (BRBNS).  (Pediatrics 2012; 129: e1080-84). This patient, an 8-year-old girl from Turkey) presented with massive gastrointestinal bleeding had multiple venous malformations all over her body, especially throughout her gastrointestinal tract.

Before instituting sirolimus, patient had failed several agents: prednisolone, interferon-α, propranolol, and aminocaproic acid.  Sirolimus was dosed at 0.05-0.1 mg/kg as an antiangiogenic agent with a goal of maintaining a trough level between 1 and 5 ng/mL.  The lesions decreased in size but did not disappear.  Initially, patient received therapy with propranolol concomitantly.  Dramatic improvements in hemoglobin were noted after starting sirolimus therapy.

Additional references:

  • -Pediatr Blood Cancer 2011; 57: 1018-24.  Use of sirolimus for complicated vascular anomalies in children
  • -Pediatrics 2001; 107: 418.  Case report of BRBNS
  • -JPGN 2001; 33:183-188. Use of octreotide in BRBNS

How to stop HBV vertical transmission

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A review and a study this month help delineate a strategy to lower the rate of HBV transmission (Clin Gastro Hepatol 2012; 10: 452-59 & 520-526).  Overall, using HBIG and HBV vaccine within 12 hours of birth (followed by two additional doses of vaccines within 6-12 months) prevents about 95% of HBV transmission from HBsAg-positive mothers to their infants.  This has made a huge difference.  Yet, among mothers with high levels of viremia, HBV is still transmitted in 8-30%.  As such, this review proposes an algorithm to reduce mother to child transmission (MTCT).

The key risk factor is HBV DNA levels >200,000 IU/mL; the most effective way to reduce transmission from highly-viremic mother to infancts is the use of antiviral therapy.  The authors recommend that in addition to the usual preventive measures (HBIG/HBV vaccine within 12 hours of birth), that efforts to lower MTCT include use of either lamivudine (pregnancy category C), telbivudine (pregnancy category B), or tenofovir (pregnancy category B) at the 3rd trimester in the following:

  • Infected women with high HBV DNA levels
  • Infected women who have had children who have failed previous prophylaxis
  • Infected women with threatened pre-term labor

In addition, elective C-section should be considered if HBV DNA >20 million IU/mL at full term.

The second citation refers to an open-label prospective study of 88 HBe-Ag positive women.  All women had HBV DNA >6 log10 copies/mL and increased ALT.  Telbivudine (600 mg/day) was administered to 53 women starting between 12 and 30 weeks gestation; there were 35 control patients who all received HBIG/HBV vaccine.  In the treatment group, none of the infants developed HBV infection.  In the control group, the transmission rate was 8.6%.  No significant adverse effects were noted; specifically, no congenital malformations were noted.

Related blog entry/additional references:

Diagnosing biliary atresia earlier

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Biliary atresia (BA) is often suspected among infants with prolonged jaundice. In fact, efforts have been underway for a long time to encourage fractionation of the bilirubin values to look for conjugated hyperbilirubinemia, especially in infants that remain jaundiced at three weeks of life.  While this is still good advice, given the lack of success in implementation, there is good evidence that obtaining a fractionated bilirubin at any time point can help identify cholestasis associated with BA.

A recent article by Karpen et al (Pediatrics 2011; 128:. e1428 -e1433) indicates that direct bilirubin values are elevated beginning within the first one to two days in patients with BA.  In their cohort of 61 BA subjects, 56% had newborn fractionated bilirubin values.  Every BA patient had elevated direct bilirubin, on average 1.4 ± 0.43 mg/dL (normal <0.5) (compared with control patients:  0.19 ± 0.075 mg/dL, P < .0001).  Also, another important finding was that early on the ratio of direct bilirubin to total bilirubin was normal in 79%; normally this ratios is ≤0.2.  As such, all patients with increased direct bilirubin need to be followed closely.

Related blog entries:

Outcomes of Biliary Atresia

MicroRNAs and biliary atresia

Bleeding due to vitamin K deficiency

Diarrhea, GC-C and guanylin

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During my fellowship, I participated in research studying the effects of guanylin and its interaction with the receptor, guanylate cyclase C (GC-C).  So whenever clinical articles demonstrate clinical significance, I am interested.  This month there is evidence that some cases of familial diarrhea are due to mutations which activate the GC-C receptor (NEJM 2012; 366: 1586-95).

The authors describe a novel dominant disease in 32 members of a Norwegian family due  to a mutation in the sequence of GUCYC which encodes GC-C.  Exposure of this mutant receptor to its ligands results in increased cyclic guanosine monophosphate (cGMP).  This in turn likely causes hyperactivation of the cystic fibrosis transmembrance regulator (CFTR)  resulting in diarrhea.  Individuals with this mutation tended to have mild chronic diarrhea with an early onset as well as a susceptibility to inflammatory bowel disease and small bowel obstruction.

While this mutation is rare, there is a larger role for GC-C.  Heat-stable enterotoxins form E. coli bind to this receptor starting a cascade which results in diarrhea.  Since there had to be a role for GC-C other than facilitating development of diarrhea after exposure to pathogens (Why would our body create a receptor for a pathogen?), researchers discovered an endogenous ligand for GC-C, guanylin.   Guanylin acts as an agonist of  GC-C and regulates electrolyte and water transport in intestinal and renal epithelia.  In addition, guanylin and GC-C serve as a model for intestinal gene regulation.  Also, GC-C has been investigated as a predictive marker for colorectal cancer and for a role in renal electrolyte transport in humans; in animals, GC-C and its ligands have been shown to have effects on behavior and satiety.  

Additional references:

  • -Steinbrecher KA, Cohen MB. Transmembrane guanylate cylase in intestinal pathophysiology. Curr Opin Gastroenterol 2011; 27: 139-45.
  • -Gastroenterology 2010; 138: 886.  Linaclotide -a guanylin analog –use for constipation.
  • -Hochman JA, Sciaky D, Whittaker T, Hawkins JA, Witte DP, Cohen MB. “HNF-1 Regulates the Transcriptional Activation of Guanylin” Am. J.  Physiol. 273 (Gastrointest. Liver Physiol. 36): G833-G841, 1997.
  • It’s often elemental  Previous post discusses protracted diarrhea of infancy

Oley: Check it out

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Recently, I received a post from Oley Foundation (Linda May) asking me whether I was going to its convention.  While I am not, I did want to share that link:

http://www.oley.org/annualconf.html
The conference is in lovely Redono Beach, CA, right on the beach. We have miles of running paths, beautiful beaches, on site tennis courts, and swimming pool . To quote other MDs, “the Oley Annual conference is the most important clinical conference I attend all year…”

Also, Oley website is a good link for patients with enteral tubes, ostomies, and central lines. http://oley.org/

Many questions and how-to advice available.  For example, look at this link if interested in advice about swimming with central line, or enteral tube: http://www.oley.org/Swimming.html

One for the PPI team

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While this blog in previous posts has pointed out some shortcomings of proton pump inhibitors (PPIs), at the same time this class of medications remains a crucial part of pediatric gastroenterology practice.  In most patients, the benefits of these medications far outweigh the potential risks.

One of the risks has been a low rate of increased infections due to lowering gastric acid which provides some protection against enteric infections.  More information about PPIs show that these medications are not likely to increase the risk of small intestinal bacterial overgrowth (SIBO) (Am J Gastroenterol 2012; 107: 730-35 –thanks to Ben Gold for showing me this article).

In this retrospective study from 2004-2010, 1191 patients were included with 566 receiving PPI therapy.  Mean age: 63 years for PPI users and 59 years for nonusers. Glucose breath hydrogen testing (GBHT) for bacterial overgrowth did not differ significantly between PPI users and nonusers.  The authors acknowledge that there have been conflicting reports previously between the use of PPIs and the development of SIBO (see Table 5 of article); interestingly, SIBO with PPIs has occurred predominantly in studies from Europe.  The authors note that while achlorhydria leads to SIBO, the intermittent surges of acid production with PPIs should be sufficient to prevent SIBO.

Additional references/previous blog posts:

  • Proton pump inhibitors–infection risk with cirrhosis
  • The Medical Pendulum and Gastroesophageal Reflux
  • -Gastroenterol Hepatol 2011; 7: 10-2.  Risk of infections with PPIs.
  • -Gut 2007; 56: 802-8.  SIBO with IBS.
  • -NEJM 2010; 363: 2114. large Denmark study. 5082 fetuses with PPI exposure (out of 840,968 live births. Risk of birth defects NOT increased with exposure during 1st trimester. Possible slight increase with preconception use except with omeprazole.
  • -Gastroenterol 2010; 139: 1115. Review of safety of PPIs.
  • -Gastroenterol 2010; 139: 93. n=167,000. PPIs associated with hip fracture risk, OR 1.3, in patients with other risk factors.
  • -Gastroenterol 2010; 138: 896-904. 5 yrs of PPI -no increase risk in hip/spine fx.
  • -Arch Intern Med 2010; 170: 765-71, 747 (ed). PPI not related to hip fx (n=161,806) women 50-79. INCREASE risk of spine fx, hazard risk 1.47
  • -Arch Intern Med 2010; 170: 772-8. PPIs increase risk of CDT (hazard ratio 1.42 –42% increase in risk), n=1166.
  • -Arch Intern Med 2010; 170: 784-90. n=101,796.  Risk of nosocomial infection: OR 1.74 for daily PPI, OR 2.36 if BID Rx; thus ~70% increase risk of nosocomial infection.